Advanced Outgassing

Advanced Outgassing under vacuum

This test is used in exten­sion to ECSS-Q-70-02A (see “Standard Outgassing”) and in accord­ance to ECSS-Q-TM-70-52A (kinetic outgass­ing of mater­i­als for space).

This test, with high sens­it­iv­ity, is used for a detailed invest­ig­a­tion of the mass trans­port of mater­i­als (mass-loss due to sublim­a­tion, evap­or­a­tion, outgass­ing as well as rede­pos­ition of evap­or­ated particles) under thermal vacuum. Since a vacuum microbal­ance records mass changes on-line, this test is used in exten­sion to the screen­ing test ECSS-Q-70-02A (mass change by weigh­ing in air before and after vacuum expos­ure).

Mass loss by sublim­a­tion, outgass­ing, evap­or­a­tion and the mass gained by rede­pos­ition are meas­ured by weigh­ing (ESTEC-stand­ard) in an appar­atus built accord­ing to the ESTEC-design.

sublimation_and_redeposition

Smallest mass changes can be determ­ined and accel­er­ated tests can be carried out. By on-line mass spec­tro­scopy the species of the outgass­ing or evap­or­ated particles can be analysed. For surface condi­tion­ing a sput­ter-ion-gun can be used. For evap­or­a­tion a Knudsen-cell is built in, recon­dens­a­tion on any susb­trates can be meas­ured using the microbal­ance. Calibration of impinge­ment rate is done using a quarz crys­tal microbal­ance. If neces­sary asso­ci­ated exam­in­a­tions (e.g. LO and Scanning-Electron Microscopy, IR-Spectroscopy, Auger-Spectroscopy) can be made.

Test characteristics

On-line Measurement of:

  • Mass-loss as a func­tion of time and temper­at­ure
  • Mass-gain as a func­tion of substrate, time and temper­at­ure
  • Mass spec­tro­scopy of outgass­ing and evap­or­at­ing particles

Parameters
Temperature Between -150 °C and + 800 °C, also thermal cycles
Vacuum < 10-4 Pa
Specimens Max. 30 g, vari­ous geometry
Temperature control By irra­di­ation exchange
Accuracy of weigh­ing Vacuum balance drift: <5*10-7  g/h
Quartz-crys­tal micro-balance: <10-8 g/cm2